Elliot Mainzer

President & CEO
California Independent System Operator

Elliot Mainzer is President and CEO of the California Independent System Operator (ISO) in Folsom, California. For the last 25 years, he has been a leader in helping to achieve a reliable and affordable clean energy transition by working to support innovation and creativity in renewable energy development, transmission planning, market design and regional collaboration.

Mainzer joined the ISO on September 30, 2020 after an 18-year career at the Bonneville Power Administration (BPA), including seven years as Administrator and CEO. At BPA, he led efforts to unlock the wind-energy potential of the Pacific Northwest, managed the development of BPA’s open-season model for transmission subscription and queue management, and worked to balance the needs of the Federal Columbia River Power System with the welfare of tribal nations and salmon protection.

Under Mainzer’s leadership at the ISO, the organization has strengthened coordinated power and transmission planning with California’s regulatory agencies, integrated record-setting amounts of new power generation and the world’s largest fleet of lithium-ion batteries, helped preserve overall system reliability during the record-setting Western heat wave of September 2022 and provided strategic leadership and direction for the ISO’s new extended day-ahead market proposal. Mainzer’s strong background and personal commitment to regional collaboration as an essential element of a reliable and affordable clean-energy transition have been a hallmark of his leadership at the ISO, where he has also brought renewed focus on control center modernization, stakeholder engagement and program management in support of the organization’s new 2022-2026 strategic plan.

A native of San Francisco, Mainzer has an undergraduate degree in geography from U.C. Berkeley and master’s degrees in Business Administration and Environmental Management from Yale University. He is a senior fellow of the Oregon Chapter of the American Leadership Forum, has served on the boards of the Electric Power Research Institute and the Energy Systems Integration Group, and currently serves as co-chair of the Western Electric Industry Leaders Group.

He and his wife Margaret have twin boys. Among his non-professional pursuits, Mainzer is an amateur jazz saxophonist and dedicated student of jazz theory and history.